The present invention relates to apparatus for manipulating sheets in general, and more particularly to improvements in apparatus for manipulating folded sheets in bookbinding and/or analogous machines. Still more particularly, the invention relates to improvements in apparatus for removing successive folded sheets from a stack or row of neighboring sheets.
U.S. Pat. No. 3,199,862 discloses an apparatus wherein a transfer conveyor receives successive folded sheets from a stack and delivers such sheets into a guide wherein each inserted sheet is caused to abut against a stop in order to ensure predictable delivery into the range of a pair of rotary spreading devices which open up the sheet prior to transfer or descent of the opened sheet onto an evacuating conveyor. The patented apparatus and similar apparatus which are presently used for analogous purposes can process up to but normally fewer than 14,000 sheets per hour. If the output of such apparatus is increased beyond the just mentioned number, those portions of the sheets which strike against the stop are likely to be deformed or to rebound on impact against the stop. This can prevent predictable engagement of successive sheets by the aforementioned spreading devices of the opening mechanism which ensures that the folded sheets are converted into inverted V-shaped bodies capable of descending onto a saddle-like portion of the evacuating conveyor. Misalignment of folded sheets during transport from the stack onto the evacuating conveyor can result in prolonged interruptions of operation of the apparatus and substantial losses in output, even at the aforementioned rate of processing fewer than 14,000 sheets per hour.